Thats my question...i want to do a cat back exaust system but ive read that you shouldnt go any more then 2" pipe on an nx2000 because you might actually lose power. Im thinking i should bump it up to 2.25", but i dont want to sacrifice any torque either...what do u guys use and what do u feel is the most effective. thanks in advance.

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1992 Nissan NX2000
White...fully loaded

The 2.25 is the most common size people get. I'm going to do the same too really soon on my NX,
I always here stuff about back pressers and what not for exhaust systems but no one ever talks about scavenging could some one shed light on that ?

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http://members.home.net/nick18a/NXTAGjpg.jpg
92 NX2000, kyb agx, intrax springs, jwt pop,
3a Racing muffler with bonzi tip,
17 " mille miglia mm 112, Yokohama avid h4
ACT clutch on order

Im looking to do the intake, and exaust and pulley's, and maybe later on down the line headers....what are the disadvantages of using 2.25 if any?? should i automatically use 2.25 if i go with crush bends??

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1992 Nissan NX2000
White...fully loaded

For a naturally aspirated SR20, 2.25 seems to be the best. Going to a larger exhaust system will not cause you to lose power, but you will lose torque. Crush bends are more restrictive than mandrel bends so I would think 2.5" crush bends would be better.

Scavenging is what a header does. With a stock manifold, exhaust gasses from each cylinder get dumped into the same space, causing turbulence and decreasing the efficiency of the exhaust system. On a header, each cylinder dumps into it's own primary which is a tuned length so that the vacuum created by an exhaust pulse on one cylinder actually helps the flow of exhaust gas out of another cylinder.

I know that explanation is kinda awkward. Let me know if you want me to try again.



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Paul
'92 NX2000 w/ mods

i have a few mods on my car and one is the 2.25" catback exhaust. when installing the japan motor with the header, i didnt tighten the flexpipe to the cat good, so it had a decent size leak. when all was done i took the car out for a spin and it was sooo fast. i fixed the exhaust leak and lost a noticeable amount of power! so i just hollowed the cat (my friend does the inspection stickers http://laf.cioe.com/~benbobbo/NonCGI/wink.gif) and the power is even better than before, moral to the story is that i would get 2.5" piping if its crush bends or 2.25" if its mandrel bent. it will work really good and you can leave your cat.

I say 2.25" with mandrel bends if you plan on going with all the bolts and cams. Otherwise just go with 2" with mandrel bends.

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Thomas Fox
'93 NX2000
www.geocities.com/subcltr_nx2000/Homepage.html (http://www.geocities.com/subcltr_nx2000/Homepage.html)

<font face="Verdana, Arial" size="2">Crush bends are more restrictive than mandrel bends so I would think 2.5" crush bends would be better.</font>

I wouldn't use 2.5" with crush bends. The restriction caused by the crush bends will create more restriction that the larger diameter pipe can compensate for.

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Thomas Fox
93 NX2000
http://www.geocities.com/socalserca/Homepage.html
http://www.geocities.com/subcltr_nx2000/Homepage.html
http://sites.netscape.net/napsz/importgarage